My system is as follows:

P1-166MMX, 64MB EDO DRAM, S3 something-or-other PCI graphics, socket 7 ATX motherboard (probably ATX v1.2 or earlier), WD 8.4GB IDE, Windows 2000 SP4.

The reason for the archaicness of the specs is because this system has been built up as a test platform for a combined UPS/PSU concept study.

Which brings me to:

I am considering designing and building a combined UPS/PSU - basically a PSU with a big battery attached to it, a simple charging circuit, a switching circuit and an assortment of other complicateds.

Because of the theoretical nature of what I'm attempting, the system I'm attempting this on is very disposable. Pity the 486 never came out in ATX...

I have a copy of the ATX v2.2 PSU required specs, an electronic engineering degree, the appropriate tools and testing equipment, an electronic components supplier and a complete disregard for personal safety. Anything else I need?

I feel that this might be an ambitious small project, and am mainly looking for advice, comments and opinions here. So let's hear 'em!

Should be feasible with your knowledge and resources. I will be curious to see what you come up with, hopefully it lasts a little longer than your overvolted pumps

Curious what kind of battery you plan on using? I think most used in UPS are simple acid/lead batteries but I don't know a ton about PC UPS batteries. Wonder if you could get by on something smaller and lighter since the system requires such little power.

And are you planning to design a standby UPS or a line-interactive UPS? Or what are you planning for that?

Sounds like a fantastic project for a geek minded enthusiast! Kudos to you for a very interesting project. With the resources you described and a few sparks flying here and there, I'd say it's very feasible to do and wish you much luck!

Given you can buy a UPS for less than $100, I have to ask why (as if we need a real reason to do anything geek-worthy)? Because? $hit$ and giggles? Potential product development?

Regardless of the reasons, post the results!

Knowing Mugz, this one is for the sake of tinkering, not to really accomplish something for his personal use.

I'm not going to be too specific on the actual details yet, but what I can reveal thus far is that there are going to be two separately switched 12V supplies - one a 'smart' battery charger, permanently fed off 240V mains, and the other linked to ATX switch-on/switch-off logic.

@Tool
Feasible, yes, and ambitious. The overvolted pumps was not meant to last - that was proving a point only. This is mainly just for the heck of it (well-spotted), although if it works well enough I might end up trying to turn it into a commercial venture.

Almost all UPSs I've encountered have used sealed lead-acid batteries - compact car batteries, basically. Later on it'll probably run NiMH or NiCd batteries.

It'll probably be considered best as a hybrid between standby and line-interactive, although if you consider a normal UPS as coming in the line before the PSU, this one comes in as part of the PSU.

Like this: 240V Mains -> UPS -> 240V protected -> PSU -> PC electronics.
Mine: 240V Mains -> 13.8V PSU -> Battery -> 12V/5V/3.3V VRMs -> PC.

It'll be a UPSU.

The biggest challenge will be the switch-on (ATX) logic, the green wire and the grey wire, but if someone else designed it I can reverse-engineer it.

@chunkymonster
Mostly for fun, although I could potentially develop this concept into a product. We'll see.

Incidentally, can anybody recommend an online pictures hosting site that I can drop photos of this (and maybe other) projects on?